They just pop out ,mine are soaking in a bowl of hot water with Bicarbonate of soda that will clean the crud out.
It might be worth checking the silly pipe joiner ,you will have to undo a few of the torx screws(size 20) & put the wipers in the upright position, no need to take the scuttle panel off as you can pull the pipe out & the joiner will come out. This joiner has a diaphragm with a spring loaded "Damper" in the top. This clogs up & sticks closed or just lets one pipe open & keeps the other closed.
Its rubbish so I gutted mine & refitted the membrane with the top but without the spring &plunger, it belts it out now.